What is VBAC?

VBAC stands for Vaginal Birth After Caesarean delivery.

Women who delivered a baby by caesarean Section (c-section) in the previous pregnancy will be counselled to choose either an elective caesarean delivery in the subsequent pregnancy, or a vaginal birth. Dr Tang believes that a vaginal delivery is a safe option after caesarean delivery for many women.

What are the advantages of having a VBAC?

– Reduced risk of blood clot in the leg or lung, a complication associated with surgery and immobilisation.

What are the risks associated with VBAC?

Having a vaginal birth after caesarean delivery is not without risk. During a caesarean delivery, the uterus is surgically opened. Although the surgical incision (cut) heals, there is an increased risk of uterine rupture (tearing open of the uterine wall) during future deliveries.

In general, women who undergo VBAC have a low risk of uterine rupture. However, the risk of uterine rupture is higher with VBAC than with repeat caesarean delivery.

The risk of uterine rupture depends in part upon the type of incision made during the first cesarean delivery. Transverse (horizontal) incisions, where the surgical cuts are done from side to side in the lower part of the uterus, are commonly used and have the lowest risk of rupture (0.5% or 1 in 200 cases). The risk is higher with other types, such as T-shaped or vertical incisions, where the surgical cuts are done from top to bottom on the uterus (4 to 9 % risk). It is important to realize that the direction of the skin incision does not indicate the type of uterine incision; a woman may have a vertical skin incision and a horizontal uterine incision.

The rate of fetal death is very low with both types of delivery. However, because the risk of fetal death increases with uterine rupture, fetal death occurs more frequently with VBAC than with repeat cesarean delivery. It is estimated that about one birth in 20 uterine ruptures can result in a stillbirth, however, this risk must be viewed in the context that any labour is associated with some risk to the baby, and the risks to the baby during VBAC where contraindications (see below) are excluded, are generally regarded as similar to those faced by a baby who is the vaginal first-born to any mother.

Maternal death is very rare with either type of delivery, there is however a 1 in 10 chance of needing a hysterectomy if the uterus has ruptured during labour.

– have a previous surgery to the uterus where the uterine cavity has been opened, e.g. myomectomy (removal of uterine fibroids)

– have pelvic problems or abnormalities that prevent vaginal delivery

– require induction of labour for a medical reason and the cervix has not ripened (widen and shorten enough to allow breaking of water, see induction of labour).

What is the chances of success in attempting a VBAC?

In general, 60 to 80 percent of women who attempt VBAC have a successful vaginal birth. The chances are increased if the woman:

– Has had a vaginal delivery or VBAC in the past

– Experiences spontaneous onset of labour (labour is not induced)

– Has a normally progressing labour, including dilation and effacement (thinning) of the cervix

– Had a prior caesarean delivery due to the baby’s position (breech).

– Had the prior caesarean delivery early in labor, not after full cervical dilatation

Will the labour be managed any differently when attempting a VBAC?

A woman who attempts VBAC is managed similarly to other women anticipating a vaginal delivery. Women who attempt VBAC under the care of Dr Tang will be monitored by a fetal heart rate monitoring device call CTG to monitor for early signs of fetal distress and uterine rupture, this is done continuously throughout the labour. Medications to induce labour or improve contractions (syntocinon) will be used cautiously since they can increase the risk of uterine rupture. If problems occur during labour, a caesarean delivery may be recommended.